Hi Chris,
I don't fully understand your objections to the approach taken.
Is there a compatibility issue with the addition of the additional
methods to MulticastSocket?
I don't see Datagram.setReuseAddress(...) handling the SO_REUSEPORT
option, this has to be done explicitly via setOption at this level of
abstraction.
MulticastSocket is a subclass of DatagramSocket (that in itself is a
questionable structuring), and as such
has specialized behaviour, and part of that specialization is the
setting of the setting SO_REUSEADDR and SO_REUSEPORT
in its constructors, to enable address reuse semantics, prior to binding
an address.
As part of that specialization, it would seem appropriate that
MulticastSocket manipulate the SO_REUSEPORT
option in a consistent way. Adding an overridden setReuseAddress(...)
method provides that consistency and
encapsulates the specialized behaviour.
Is alternatively proposal to NOT do anything to MulticastSocket, BUT
document clearly how to handle the failing scenario, that an MulticastSocket
requires both setReuseAddress() and a setOption call to disable
reuseaddress semantics on an unbound MulticastSocket ?
This then raises the question of why have a convenience method, such as
setReuseAddress() in the first place, when it can be handled
adequately via the setOption
regards
Mark
On 14/09/2016 13:34, Chris Hegarty wrote:
Mark,
On 14/09/16 13:23, Mark Sheppard wrote:
Hi Chris,
so are you accepting that it is correct to add the overridden
methods in MulticastSocket and that these need
appropriate javadoc ?
I think we need these, but they should just call their super
equivalents, i.e. no implicit setting of SO_REUSEPORT. They would
exist solely as a place to locate guidance, or a note, that one
will likely want to set SO_REUSEPORT too.
or are you advocating pushing the handing of the SO_REUSEPORT into the
base DatagramSocket class ?
It is already there. I am not proposing to change this.
It is not clear how your code changes fit in the proposed fix i.e. the
explicit setting of the option to false?
My proposal is an alternative. It is not related to the current
webrev.
With the current proposed changes then I think it would be sufficient to
invoke setReuseAddress(true) in MulticastSocket constructors
rather than
// Enable SO_REUSEADDR before binding
setReuseAddress
<https://java.se.oracle.com/source/s?defs=setReuseAddress&project=jdk9-dev>(*true*);
// Enable SO_REUSEPORT if supported before binding
*if* (supportedOptions
<https://java.se.oracle.com/source/xref/jdk9-dev/jdk/src/java.base/share/classes/java/net/MulticastSocket.java#supportedOptions>().contains
<https://java.se.oracle.com/source/s?defs=contains&project=jdk9-dev>(StandardSocketOptions
<https://java.se.oracle.com/source/s?defs=StandardSocketOptions&project=jdk9-dev>.SO_REUSEPORT
<https://java.se.oracle.com/source/s?defs=SO_REUSEPORT&project=jdk9-dev>))
{
*this*.setOption
<https://java.se.oracle.com/source/s?defs=setOption&project=jdk9-dev>(StandardSocketOptions
<https://java.se.oracle.com/source/s?defs=StandardSocketOptions&project=jdk9-dev>.SO_REUSEPORT
<https://java.se.oracle.com/source/s?defs=SO_REUSEPORT&project=jdk9-dev>,
*true*);
}
as the overridden setReuseAddress takes care of SO_REUSEPORT
Yes, this is what Vyom has proposed, in the webrev.
I would like to explore an alternative, so see what it would look like.
-Chris.
regards
Mark
On 14/09/2016 11:43, Chris Hegarty wrote:
Vyom,
On 11/09/16 08:01, Vyom Tewari wrote:
Hi All,
Please review the below code change.
Bug : https://bugs.openjdk.java.net/browse/JDK-8153674
Webrev :
http://cr.openjdk.java.net/~vtewari/8153674/webrev0.0/index.html
<http://cr.openjdk.java.net/%7Evtewari/8153674/webrev0.0/index.html>
This change override the "get/setReuseAddress" for MulticaseSocket
and
will abstract with both reuse attributes(SO_REUSEADDR & SO_REUSEPORT).
This issue arises since the changes for 6432031 "Add support for
SO_REUSEPORT" [1], which sets SO_REUSEPORT on MulticastSocket, if
the available. So setting setReuseAddress(false) alone is no longer
sufficient to disable address/port reuse, one must also set
SO_REUSEPORT to false.
I would be really nervous about changing set/getReuseAddress, without
at least updating the javadoc to indicate that it is now, for MS,
operating on two socket options. Although, I do have sympathy
here since SO_REUSEPORT and SO_REUSEADDR are almost identical when
dealing with multicasting.
An alternative, maybe; Since the MS constructors document that
SO_REUSEPORT will be set, where available, maybe a javadoc note
on the set/getReuseAddress methods would be sufficient, that
indicates that StandardSocketOptions#SO_REUSEPORT may also need
to be set to have the desired effect?
If so, then code would have to:
setReuseAddress(false);
if
(supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT))
this.setOption(StandardSocketOptions.SO_REUSEPORT, false);
, but at least it is explicit.
Q: not all MS constructors document that SO_REUSEPORT is set, but
they should, right? This seems to have slipped past during 6432031 [1].
-Chris.
[1] https://bugs.openjdk.java.net/browse/JDK-6432031
